The reader does't know what Thanatos and his Master did behind the scenes and who they were able to trick fate while David senior was not.
Dave was meant to die. Most of the time by getting gun downed or driven over by one of Memphis Goons. as Memphis was destined to kill or order some killing around day 24 to kill.
Speculating:
Thanatos and his Master find a variance to keep Dave alive be bringing him to the mountain. But doing so either result in the Death of everyone, everyone except Dave (and Oswin), or just Dave first followed by everyone else. So someone was killed to appease DEATH, so Dave could live.